As for vacuum secondaries, I have never found a need for anything other than vacuum secondaries on the street. If you are considering the street demon it only comes with those. You may have 'never found a need for anything other than vacuum secondaries on the street', but our favorite manufacturer (Mopar) used mechanical secondaries more than anything else. Only the later Holleys used vacuum. ALL of the Carters (AFBs, AVSs, Thermoquads) used mechanical secondaries. And that was on everything from 273s to Hemis. Not totally accurate, while it's true the actual throttle butterflies were mechanically actuated, the air door in the top prevented them from actually doing anything until that air valve opened as the engines ability to ingest the extra air and fuel increased creating the same effect as a Holley type of vacuum actuated carb. So TQs, QJs, AFBs and AVSs are really considered to be vacuum secondary carbs as the secondaries only work as the engine demands and not the throttle.
"Follow me the wise man said, but he walked behind"
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion.
'74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost conversion.
2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
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